Electrochemical device such as electrochromic or photovoltaic device and electrical connection means thereof

ABSTRACT

The subject of the invention is an electrochemical device, especially an electrically controllable system with variable energy and/or optical properties or a photovoltaic device, comprising at least one substrate ( 1 ) carrying an electroactive stack of layers ( 3 ) arranged between an electrode called a “lower” electrode and an electrode called an “upper” electrode. Each electrode comprises at least one electroconductive layer ( 2 ) in electrical contact with at least one current lead. These current leads are arranged outside the region of the carrier substrate ( 1 ) which is covered by the stack of electroactive layers ( 3 ).

[0001] The subject of the present invention is an electrochemicaldevice, especially an electrically controllable system of the glazingtype and with variable energy and/or optical properties or aphotovoltaic device.

[0002] At the present time, there is an increased demand for glazingcalled “intelligent” glazing capable of being adapted to the needs ofthe users.

[0003] There is also an increased demand for photovoltaic glazing, whichmakes it possible to convert solar energy into electrical energy.

[0004] With regard to “intelligent” glazing, this may involvecontrolling the amount of sun passing through glazing mounted externallyin buildings or vehicles of the automobile, train or aircraft type. Theaim is to enable excessive heating inside passenger compartments orpremises to be limited, but only in the case of strong sunshine.

[0005] It may also involve controlling the degree of vision throughglazing, especially so as to cloud them, make them diffusing or even toprevent any vision when that is desirable. This may relate to glazingmounted as interior partitions in premises, trains, aircraft or mountedin the side walls of an automobile. This also relates to mirrors used asrear-view mirrors, in order to promptly prevent the driver gettingdazzled, or signaling panels, in order that messages appear when this isnecessary, or intermittently in order to attract attention better.Glazing which can be made diffusing at will can be used when desired asprojection screens.

[0006] There are various electrically controllable systems which makethis sort of modification in appearance or thermal properties possible.

[0007] To modify the light transmission or the light absorption of theglazing, there are systems called viologen systems, such as thosedescribed in patents U.S. Pat. No. 5,239,406 and EP-612 826.

[0008] To modify the light transmission and/or the thermal transmissionof the glazing, there are also systems called electrochromic systems.These generally comprise, in a known manner, two layers ofelectrochromic material separated by an electrolyte layer and surroundedby two electroconductive layers. Each of these layers of electrochromicmaterial may reversibly insert cations and electrons, the alteration oftheir oxidation state following these insertions/deinsertions leading toan alteration in their optical and/or thermal properties.

[0009] It is common practice to put the electrochromic systems intothree categories:

[0010] that where the electrolyte is in the form of a polymer or a gel;for example, a proton conductive polymer such as those described inpatents EP-253 713 or EP-670 346 or a lithium-ion-conducting polymersuch as those described in patents EP-382 623, EP-518 754 and EP-532408, the other layers of the system generally being mineral in nature,

[0011] that where the electrolyte is mainly a mineral layer. Thiscategory is often called an “all-solid” system, examples thereof can befound in the patents EP-867 752, EP-831 360, the patent FR-99/03420filed on Mar. 19, 1999 corresponding to patent PCT/FR00/00675 filed onMar. 17, 2000, the patent FR-2 781 084 corresponding to the patent offiling number WO/FR99/01653, filed on Jul. 8, 1999,

[0012] that where all the layers are polymer-based, a category which isoften called an “all-polymer” system.

[0013] There are also systems called “light valve” systems. Theseinvolve films comprising a polymer matrix which is generallycrosslinked, in which microdroplets, containing particles which arecapable of placing themselves in a favored direction under the action ofa magnetic or electric field, are dispersed. A light valve comprising apolyorganosilane matrix and particles of the polyiodide type, whichintercept much less light when a voltage is applied to the film, is alsoknown from patent WO93/09460.

[0014] Systems called liquid crystal systems may also be mentioned, witha mode of operation similar to the above. They are based on the use of apolymer-based film placed between two conductive layers, in whichdroplets of liquid crystals, in particular nematic liquid crystals withpositive dielectric anisotropy, are arranged. When a voltage is appliedto the film, the liquid crystals orient themselves along a favored axis,which enables vision. Without the voltage, in the absence of crystalalignment, the film becomes diffusing and prevents vision. Examples ofsuch films are described, in particular, in European patent EP-0 238164, and American patents U.S. Pat. No. 4,435,047, U.S. Pat. No.4,806,922, U.S. Pat. No. 4,732,456. This type of film, once interposedand incorporated between two glass substrates, is marketed bySaint-Gobain Glass under the commercial name “Priva-Lite”.

[0015] In fact it is possible to use all the liquid crystal devicesknown under the names of “NCAP” (Nematic Curvilinear Aligned Phase) or“PDLC” (Polymer Dispersed Liquid Crystal).

[0016] It is also possible to use, for example, cholesteric liquidcrystal polymers, such as those described in patent WO92/19695.

[0017] All these systems have in common the need to be equipped withcurrent leads to supply electrodes generally in the form of twoelectroconductive layers on each side of the layer or various activelayer(s) of the system.

[0018] These current leads are often in the form of metal clips placedabove and below the glazing region provided with the active layer orlayers. They are perceived as unesthetic, hence the need to hide them byvarious means. This masking of the periphery of electricallycontrollable systems complicates their manufacture and moreover reducesthe “active” area of the glazing that can be exploited by the user.

[0019] The aim of the invention is therefore to provide an improvedconnection for the electrically controllable systems of the glazing typewhich have been mentioned above. In particular, it has the aim ofproviding a connection which is better from a visual and/or electricalpoint of view and which, preferably, remains simple and flexible toimplement on the industrial scale. It relates to all the systems listedabove, and more specifically to the electrochromic glazing called“all-solid” glazing.

[0020] The subject of the invention is firstly an electrochemical deviceof the type described above, which comprises at least one substratecarrying an electroactive stack of layers arranged between an electrodecalled a “lower” electrode and an electrode called an “upper” electrode,each comprising at least one electroconductive layer. Each of theelectrodes is in electrical contact with at least one current lead.According to the invention, these current leads are arranged outside theregion of the carrier substrate which is covered by the stack ofelectroactive layers.

[0021] In the sense of the invention, the term “lower” electrode refersto the electrode which is closest to the carrier substrate taken as areference, on which at least part of the active layers (all the activelayers in an “all-solid” electrochromic system) is arranged. The “upper”electrode is the one placed on the other side, with respect to the samereference substrate.

[0022] The invention is applicable to glazing in the broadest sense: thecarrier substrate is generally rigid and transparent, of the glass orpolymer type such as polycarbonate or polymethylmethacrylate (PPMA).However, the invention includes polymer-based substrates which areflexible or semiflexible.

[0023] Generally, the electrodes are transparent. However, one of themmay be opaque if the glazing operates not in transmission but inreflection (mirror).

[0024] The active system and the upper electrode are generally protectedby another substrate of the rigid type, possibly a laminate includingone or more thermoplastic polymer films of the EVA (ethylene vinylacetate), PVB (polyvinyl butyral) or PU (polyurethane) type.

[0025] The invention also includes protection of the system by aflexible or semiflexible substrate, in particular a polymer-basedsubstrate.

[0026] It is also possible to avoid a lamination operation carried outin the hot state, possibly under pressure, by substituting theconventional thermoplastic interposed film with a double-sided adhesivefilm, whether supported or not, which is commercially available andwhich has the advantage of being very thin.

[0027] In the sense of the invention, and for the sake of concision, theterm “active stack” or “electroactive stack” denotes the active layer orlayers of the system, that is to say all the layers of the system exceptfor the layers belonging to the electrodes. For an electrochromicsystem, it therefore mainly consists of a layer of an anodicelectrochromic material, an electrolyte layer and a layer of a cathodicelectrochromic material, it being possible for each of these layers toconsist of a monolayer or a plurality of concurrent superimposed layershaving the same function.

[0028] Generally, each electrode contains one electroconductive layer orseveral superimposed electroconductive layers, which will be consideredhenceforth as a single layer. Generally, two current leads, placed alongthe two opposed edges of the layer when it has the outline of arectangle, a square or a similar geometric shape of the parallelogramtype, are needed in order to supply the electroconductive layercorrectly.

[0029] Commonly, these leads are in the form of clips, that is to sayopaque metal strips which are generally copper-based and often silvered.The clips, especially with regard to the “upper” electrode, are placedon its face opposite to that in contact with the active stack. Since thestack and the electroconductive layer in question have generally thesame dimensions, this means that 1 or 2 cm of the assembly must behidden once the system is completed, in order to hide the region of theglazing provided with clips. According to the invention, the procedureis different since these current leads are taken away from the activestack. Even if this masking remains necessary, it will not hide a largeportion of the “active” area of the glazing.

[0030] In the invention, the dimensions of the active stack are almostthe dimensions of the electrically controllable area accessible to theuser, and there is no or little loss of active area, in any case muchless than the loss of area caused by the usual placement of clips on theactive stack.

[0031] Apart from this considerable advantage, the invention has anotherbenefit, namely it is guaranteed that the placement of the clips willnot risk damaging the active stack. There is no local overthickness inthe glazing due to the presence of clips in the main region where theactive layers of the system are present. Finally, moving the electricalsupply of these leads away from the sensitive part of the system may befacilitated, as well as their placement itself.

[0032] The present patent application sets out firstly to describe apreferred embodiment of the “lower” electrode of the system.

[0033] Advantageously, the lower electrode may comprise anelectroconductive layer which covers at least one region of the carriersubstrate not covered by the active stack. Moreover, the benefit of thisconfiguration is that it is easy to obtain: it is possible to depositthe conductive layer, for example, over the entire surface of thesubstrate. This is in fact the case when the electroconductive layer isplaced on the glass on the glass manufacturing line itself, inparticular by pyrolysis on the ribbon of float glass. The rest of thelayers of the system may then be deposited on the glass once it is cutto the desired dimensions, with a temporary masking system.

[0034] The other benefit is that these regions of the substrate whichare only covered by the lower electroconductive layer will be able toserve for the placement of current leads “offset” according to theinvention.

[0035] An example of an electroconductive layer is a layer based on adoped metal oxide, in particular indium oxide doped with tin, calledITO, or tin oxide doped with fluorine SnO₂:F, possibly deposited on aprelayer of the silicon oxide, oxycarbide or oxynitride type, with anoptical function and/or a barrier function against alkalines when thesubstrate is made of glass.

[0036] Accordingly to a variant, the electroconductive layer of thelower electrode covers a region Z₁ of the carrier substrate whichcompletely covers the region Z₂ which is covered by the active stack,the region Z₁ having dimensions greater than the region Z₂. In this way,it is possible to have two regions Z₁ and Z₂ essentially of rectangularshape, with the region Z₁ greater than Z₂ and approximately centered onthe latter.

[0037] Alternatively, it is possible to have both regions Z₁ and Z₂essentially rectangular, the two regions partially covering each other.This then gives a scenario where there are regions of the substratewhich are covered by the electroconductive layer and not by the activestack, and vice versa.

[0038] It is also possible to have the rectangular region Z₁ exceeding,on two of its opposed sides only, the region Z₂.

[0039] The region Z₃ covered by the electroconductive layer of the upperelectrode is itself preferably essentially identical to the region Z₂covered by the active stack. Its configuration will be detailed below.The benefit of this characteristic is the simplicity of its manufacture,especially when dealing with an “all-solid” electrochromic system whereall the layers involved are deposited one after the other on a singlecarrier substrate. The layer thus has the same dimensions and the sameconfiguration as the underlying active layers of the active system. Itmay therefore be deposited after the latter, for example on a line fordepositing the layers under vacuum of the sputtering type.

[0040] We now come to the configuration of the “lower” electrode. It hasbeen seen that the lower electroconductive layer has regions not coveredby the active stack. Some will serve for the ad hoc placement of currentleads. It is also necessary to avoid any short circuit between the“bare” conductive regions and the current leads of the upper electrode.With this objective, provision is therefore advantageously made,according to a variant, to “deactivate” this lower electroconductivelayer over at least part of its periphery corresponding at least in partto a bare region, not covered by the active stack. The term“deactivated” refers to a portion of electroconductive layer which nolonger fulfills its basic function, and which no longer participates inthe electrical conduction of the rest of the layer from which it iselectrically insulated.

[0041] Preferably, these “deactivated” regions overlap a region coveredby the active stack and a region not covered by the active stack.

[0042] This deactivation will be detailed with the help of examples. Inparticular, it may involve making an incision in the layer or alocalized heat treatment, as is described, for example, in theaforementioned patent WO/FR/99/01653.

[0043] According to one embodiment of this variant, the lowerelectroconductive layer covers a substantially rectangular region Z₁ ofthe substrate, with two deactivated regions along the two opposed edgesof said rectangular region (it being possible for these regions then tobe left in contact with the upper electrode leads, since they areelectrically insulated, while it is possible to have two other regions,on the edges of the two other opposed edges, which are left bare andelectrically active for connection with the current leads of the lowerelectrode).

[0044] According to another embodiment, the lower electroconductiveelectrode comprises, over its entire periphery, a deactivated region (ontwo of its opposed edges for the reasons stated above, that is to say toavoid short circuits with the current leads of the upper electrode. Onthe two other edges, regions are nevertheless left active and bare forconnection with the current leads of the lower electrode, thedeactivated regions only being able to affect the extreme periphery ofthe layer on these two edges).

[0045] Whatever the embodiment of the localized deactivation of thelower electroconductive layer, it can be carried out, as stated above,by carrying out an incision of the layer along one or more lines. It mayinvolve a line closed around its entire periphery (deactivation over itsentire outline). The incision may also be carried out along two linescrossing the layer from one side to the other (deactivation over two ofits opposed edges), or along two lines closed along two of its opposededges (delimitation of two deactivated regions, by leaving the extremeperimeter of the layer electrically active).

[0046] The incision of the electroconductive layer may be carried outbefore depositing the other layers and therefore involves only thatlayer. The incision may also be carried out after depositing the layersof the active system and even after depositing the upper conductivelayer. In this case, when the incision line is partly under the activelayers and possibly under the upper conductive layer, all the layers areincised at this location. It should be noted that, in order todeactivate the layer locally, it is possible to carry out a localizedablation operation rather than incising it, especially before depositingthe other layers, or to deposit it with the necessary masks.

[0047] The present patent application now sets out to describe variousconfigurations for the active stack.

[0048] Independently of the possible incision of the lower conductivelayer which may simultaneously involve that of the active system, theinvention advantageously provides for deactivating the active stack overat least part of its periphery. In this case, the term “deactivated” hasa sense similar to that of the previous conductive layer. It means thatthe stack does not operate in this region, and that it remains passivelyin a given state, whatever the electrical supply. This deactivation isas marginal as possible, in order to keep the active area as large aspossible.

[0049] According to one embodiment, the electroactive stack covers asubstantially rectangular region Z₂ of the carrier substrate, with twoperipheral regions deactivated in this way, along two of its opposededges. Alternatively, the stack comprises a deactivated region over itsentire periphery.

[0050] These regions may be deactivated in a way similar to thedeactivated regions of the lower electroconductive layer describedabove, by incision of the whole stack, along two lines crossing it fromone side to the other on two of its edges or along a line closed aroundits periphery. (In this way, a proper ablation of the stack could thusbe carried out in these regions.) These incisions could be carried outafter depositing the electroconductive layer of the upper electrode,while also incising/deactivating it simultaneously. Preferably, theunderlying lower electrode is not incised simultaneously.

[0051] This deactivation is therefore superimposed with the previous: inthe case of the lower conductive layer, its local deactivation wouldaffect at least one region not covered by the active stack (two opposededges/its entire periphery).

[0052] In the case of the active stack, it generally does not affect thelower conductive layer, and may be made on the two other opposed edgesor the periphery of the stack.

[0053] This deactivation of the active stack combines with the previousdeactivation in order to avoid any risk of short circuits between thetwo “lower” and “upper” conductive layers, and has been described insome of its embodiments in the aforementioned patent WO/FR99/01653,whose teaching is incorporated in the present application.

[0054] For further details on the nature of the layers of the activestack, reference may be made to the aforementioned patents. In the caseof “all-solid” electrochromic systems, the preferred application of theinvention, the active stack comprises the superposition of layers whichare mainly mineral and which can be deposited successively bysputtering.

[0055] The protonic cathodic electrochromic material is preferablytungsten oxide which is possibly hydrated or hydroxylated. The protonicanodic electrochromic material is preferably iridium oxide or nickeloxide which is possibly hydrated or hydroxylated. The electrolyte,according to patent EP-867 752, is preferably a superposition of severallayers, comprising for example a layer of protonic cathodicelectrochromic material of the tungsten oxide type combined with atleast one other layer, in order to inhibit its electrochromic propertiesand so that it only plays the role of a vector.

[0056] The present patent application now sets out to describe thepreferred configurations of the “upper” electrode.

[0057] Advantageously, at least one of the two electrodes, and mostparticularly the upper electrode, comprises an electroconductive layercombined with a network of conductive wires or of electricallyconductive strips.

[0058] As has been seen above, the upper conductive layer generally hasthe same dimensions as the active stack and is deposited on the samedeposition line (sputtering). It generally involves layers of dopedoxide of the ITO or ZnO type doped, for example, with Al, Ga, etc. or alayer of metal of the silver type possibly combined with one or moreprotective layers which are themselves also conductive (Ni, Cr, NiCr,etc.), and with one or more protective layers and/or with an opticalrole, made of a dielectric (metal oxide, Si₃N₄). In this scenario, thequestion was to know how to “offset” these current leads outward. It hasalready been described in the aforementioned application PCT/FR00/00675how to combine the conductive layer with a material which is moreconductive than it, for example wires made of metal of the copper type,in order to significantly increase its conductivity. The aim was tohave, for electrochromic glazing, a system which has a faster switchingtime, and which attentuates the coloration front phenomenon, where thesystem colors or decolors uniformly over its entire active surface,without any longer having the color modification propagating from itsperiphery.

[0059] The present invention, by using this type of additionalconductive network, keeps these considerable advantages. But it willalso exploit another possibility offered by its presence, namely, bythese wires or these strips, it will be able to offset the current leadsaway from the surface covered by the upper conductive layer, by puttingthem in electrical contact, not with this layer, but with the ends ofthese wires or strips, configured so as to “exceed” the surface of theconductive layer.

[0060] In its preferred embodiment, the conductive network comprises aplurality of metal wires placed on the surface of a polymer film of thethermoplastic type. It is possible to affix this film to the wiresembedded in its surface on the upper conductive layer in order to ensuretheir physical contact/their electrical contact. The thermoplastic filmmay act to laminate the first carrier substrate of the glass type withanother pane of glass.

[0061] Advantageously, the wires/strips are placed essentially parallelto each other (they may be straight or corrugated), preferably in anorientation which is essentially parallel to the length or to the widthof the upper conductive layer. The ends of these wires exceed the regionof the substrate covered by the upper conductive layer on two of itsopposed sides, in particular by at least 0.5 mm, for example by 3 to 10mm. They may be made of copper, tungsten, graphitized tungsten, or evenan iron-based alloy of the nickel-iron type.

[0062] It is expedient to prevent the ends of these wires from being inelectrical contact with the lower conductive layer. It is thereforepreferred that the ends which exceed the upper conductive layer are onlyin contact with the lower conductive layer in the deactivated regionsthereof.

[0063] Alternatively or cumulatively, in order to avoid any shortcircuits with the lower conductive layer, the ends of the wires may beelectrically insulated from the latter (where they are capable of beingin contact with its active region) by the insertion of strip(s) ofinsulating material, for example polymer-based material.

[0064] It should be noted that it is possible, alternatively orcumulatively, to use the same type of conductive network for theelectrode called the “lower” electrode.

[0065] The present patent application now sets out to describe varioustypes of current leads and their arrangements in the system.

[0066] With regard to the upper electrode, according to a variant, theends of the wires/strips of the conductive network mentioned above maybe electrically connected to two current leads in the form of flexiblestrips made of an insulating polymer covered on one of their faces withconductive coatings. This type of lead is sometimes called a “P.F.C.”(Flexible Printed Circuit) or a “F.L.C.” (Flat Laminated Cable) and isalready used in various electrical/electronic systems. Its flexibility,the various configurations that can be obtained, the fact that thecurrent lead is electrically insulated on one of its faces, makes itsuse very attractive in the present case.

[0067] According to another variant, the ends of these wires are inelectrical contact with two deactivated regions of the lower conductivelayer, and these two deactivated regions are in electrical contact withthe current leads intended for the upper electrode. Conductive “clips”may conveniently be used, which clip onto the carrier substrate in theaforementioned regions. It is an original solution to use the lowerelectrode to provide the electrical connection with the upper electrode.

[0068] With regard to the current leads of the lower electrode, it ispossible to connect it electrically along two of its opposed edges inactive regions which are not covered by the active stack. These leadsmay be the clips mentioned above.

[0069] It is also possible to bring together the current leads of thelower and upper electrodes in the form of flexible strips, as mentionedabove. Thus it may involve two substantially identical strips, each onehaving a flexible support made of an electrically insulating polymerapproximately in the shape of an L (of course, many other configurationscould be envisioned for the geometric shape of the carrier substrate andof the layers with which it is provided). On one of the sides of this L,there is a conductive coating on one face. On the other side of the L,there is a conductive coating on the face opposite to the previous face.This overall system of current leads also consists of two of these “Ls”on a plastic support. In combination, they provide two conductive stripson one face for one of the electrodes and two conductive strips on theiropposed face for the other electrode. It is a compact system which iseasy to place. Close to the junction between the two edges of each L,there is a socket electrically connected to the conductive coatings ofthe leads.

[0070] It is also possible to go further with compactness, by replacingthese two “Ls” with a complete frame: in this case a strip of insulatingpolymer of approximately rectangular shape, with, on two of its opposededges, a conductive coating on one face, and similarly on its two otheropposed edges on the other face. Preferably, there is then just a singleexternal socket instead of two. The frame may be in one piece, or inseveral parts which are assembled during mounting.

[0071] The current leads of the lower and/or upper electrodes may alsobe in the form of conventional clips, for example in the form of metalstrips of the copper type which are possibly silvered.

[0072] The current leads of the lower and/or upper electrodes may alsobe in the form of a conductive wire (or several assembled conductivewires). These wires may be made of copper, tungsten or graphitizedtungsten and may be similar to those used to constitute the conductivenetwork mentioned above. They may have a diameter of from 10 to 600 μm.This type of wire is in fact enough to electrically supply theelectrodes in a satisfactory manner, and are remarkably discreet. It maybecome pointless to mask them on mounting the device.

[0073] The configuration of the current leads is very adaptable.Substantially rectangular active systems have been described in moredetail above, but they may take a large number of different geometricalshapes, in particular by following the geometrical shape of theircarrier substrate, namely a circle, square, half circle, oval, anypolygon, diamond, trapezium, square, any parallelogram etc., and inthese various scenarios, the current leads are no longer necessary foreach electrode to supply current lead “pairs” facing each other. Thus itmay involve, for example, current leads which completely surround theconductive layer (or at the very least, which follow a good part of itsperiphery). This is quite achievable when the current lead is a singleconductive wire. It may also involve point-like current leads,especially when the device is small in size.

[0074] The device according to the invention may use one or moresubstrates made of bulk tinted glass. Advantageously, if it involveslaminated glazing, the bulk tinted glass is the glass intended to beturned inward in the premises or in the inner compartment, the outerglass being clear. The tinted glass makes it possible to adjust thelevel of light transmission of the glazing. Placed on the inside, itsheating is limited by absorption. The glass may also be curved, as isthe case for applications such as an electrochromic automobile roof, inparticular.

[0075] The glazing according to the invention may comprise additionalfunctionalities: it may for example comprise an infrared reflectingcoating, as is described in patent EP-825 478. It may also comprise ahydrophilic, antireflection, hydrophobic coating, a photocatalyticcoating with antifouling properties comprising titanium oxide in anataseform, as is described in patent WO 00/03290.

[0076] The invention will be detailed below with nonlimiting exemplaryembodiments, using the following figures:

[0077] FIGS. 1 to 12: representations in top view of an “all-solid”electrochromic glazing.

[0078] All the figures are schematic in order to facilitate theirreading, and are not necessarily to scale for the various elements thatthey show.

[0079] All the figures relate to an “all-solid” electrochromic glazing,in a laminated structure with two panes of glass, in a configurationadapted, for example, to use as glazing for an automobile roof.

[0080] All the figures show a glass pane 1, provided with a lowerconductive layer 2, an active stack 3, surmounted by an upper conductivelayer, a network of conductive wires 4 above the upper conductive layerand embedded in the surface of an ethylene vinyl acetate EVA (orpolyurethane) film which is not shown for increased clarity. The glazingalso comprises a second glass pane, not shown for further clarity, abovethe EVA film 5. The two glass panes and the EVA film are secured by aknown lamination or calendering technique, by heating, possibly underpressure.

[0081] The lower conductive layer 2 is a bilayer consisting of a first50 nm SiOC layer surmounted by a second 400 nm SnO₂:F layer (the twolayers preferably deposited successively by CVD on the float glassbefore cutting).

[0082] Alternatively, it may involve a bilayer consisting of a firstlayer based on SiO₂ doped with a small amount of metal of the Al type ofabout 20 nm thick surmounted by a second layer of ITO of about 150 to350 nm thick (the two layers preferably deposited successively, undervacuum, by sputtering assisted by a magnetic field and reactive in thepresence of oxygen, possibly in the hot state).

[0083] The active stack 3 is decomposed as follows:

[0084] a first layer of anodic electrochromic material made of(hydrated) iridium oxide IrO_(x)H_(y) from 40 to 100 nm thick, (it maybe replaced by a layer made of hydrated nickel oxide),

[0085] a layer made of 100 nm tungsten oxide,

[0086] a second layer made of 100 nm hydrated tantalum oxide,

[0087] a second layer of cathodic electrochromic material based on 370nm tungsten oxide H_(x)WO₃.

[0088] All these layers are deposited in a known manner by reactivesputtering assisted by a magnetic field.

[0089] The upper conductive layer is a layer of ITO from 100 to 300 nmthick, also deposited by reactive sputtering assisted by a magneticfield.

[0090] The conductive wires 4 are mutually parallel straight wires madeof copper, deposited on the EVA film 5 by a technique known in the fieldof windshields having heated wires, for example described in patentsEP-785 700, EP-553 025, EP-506 521, EP-496 669. Schematically, itinvolves using a heated pressing roller which presses the wire into thesurface of the polymer film, the pressing roller fed with wire from afeed reel using a wire guide device.

[0091] The EVA film 5 has a thickness of about 0.8 mm.

[0092] The two glass panes are made of standard silica-sodalime clearglass each about 2 mm in thickness.

EXAMPLE 1

[0093] This is the configuration shown in FIG. 1:

[0094] The lower conductive layer 2 covers the whole area of the glasspane. Its margins are set along two incision lines l₁, l₂ on its twosmallest opposed sides (layer with overall rectangular shape), by meansof a laser. The incision lines also affect the active system and theupper electrode since they are made after depositing all the layers.These two lines therefore delimit two regions s₁ and s₂ which aredeactivated for the whole electrochromic system, including the twoelectrodes.

[0095] The margins of the active system and the upper conductive layer 3are also set along two other incision lines l₃, l₄, after depositing allthe layers. These incisions do not affect the lower conductive layer,and are made on the longest edges of the system and of the upperconductive layer. The active system and the upper conductive layer alsocover a rectangular region of the substrate, with dimensions less thanthose covered by the lower conductive layer. These two rectangularregions are centered one with respect to the other. The incision linesl₁, l₂ on the one hand and l₃, l₄ on the other hand are thereforemutually perpendicular. The incisions l₃, l₄ delimit two deactivatedregions s₃, s₄ of the active system 3, therefore two other passiveregions of the electrochromic glazing in its entirety.

[0096] The current leads 6 are symmetrical with each other: they involvetwo strips 6 a, 6 b of an approximately L-shape, made of an insulatingpolymer. On the shortest side of the two Ls, there is a conductivecoating 7 turned toward the wires 4. On the longest side of the two Ls,there is a conductive coating 8, shown in dotted line since it is on theother face, on the face turned toward the lower conductive layer 2.

[0097] The conductive coatings 7 are in electrical contact with thewires 4, and therefore provide, via these wires 4, the electrical supplyto the upper electrode. The end of these wires, outside the surfacecovered by the stack 3, is only in contact with the insulating polymersupport of the leads 8 or with the deactivated regions s₁, s₂ of thelower electrode: in this way, any risk of short circuits between thesewires and the lower electrode is avoided.

[0098] The conductive coatings 8 are in contact with the regions of thelower conductive layer 2 which are active and not covered by the stack3: they make it possible to power the lower conductive layer 2. For eachof these current leads, there is a socket 12 placed approximately in theangle of the L of the current lead, with electrical connections suitablefor each of the conductive coatings 7 and 8.

EXAMPLE 2

[0099] This is the configuration shown in FIG. 2 which is quite similarto that of example 1.

[0100] The difference with example 1 resides in the way in which themargins of the lower conductive layer 2 are set: in example 2, theincision is carried out along a closed line l₅, which delimits aninactive region s₅ over the entire periphery of the lower conductivelayer, and over two opposed edges of the active system (as in theprevious case).

EXAMPLE 3

[0101] This is the configuration shown in FIG. 3 and which is a variantof the two preceding figures. This time, the margins of the lowerconductive layer 2 are set along two closed lines l₆, l₇ which have asubstantially rectangular outline, partly on the region covered by theconductive layer 2, partly on the region also covered by the activestack 3. As in Example 1, there are also two deactivated regions s₆, s₇on the two opposed edges of the layer 2, delimited by the two lines l₆and l₇, and which therefore do not go up to the extreme perimeter of thelayer.

[0102] These three examples therefore have in common that theydeactivate the electrochromic glazing on two of its opposed edges, inregions overlapping the region covered only by the lower conductivelayer, and the region covered both by this layer and by the active stack3.

EXAMPLE 4

[0103] This is the configuration shown in FIG. 4. The margins of thelower conductive layer 2 are set as in Example 1, along two linescrossing from one side to the other of the layer on its two smallestopposed sides. The margin setting of the active stack 3 is alsoidentical to that carried out in Example 1.

[0104] This is the type of current lead which changes: in this case,conductive clips 9, 9′ are used in order to supply the lower conductivelayer 2 and conductive clips 10, 10′ in order to supply the upperelectrode.

[0105] These clips are commercial products which are able to clip ontothe glass pane rendered conducting, and available in various sizes.

[0106] For the lower conductive layer 2, these clips 9, 9′ are fixed soas to cover the edge of the glass pane, so as to be electricallyconnected to the edges of the layer 2 which are active. They have alength less than the length separating the two incision lines of thelayer.

[0107] For the upper electrode, FIG. 4 shows the second glass pane 11,which is smaller than the glass pane 1, the clips 10, 10′ being clipped,like the clips 9, 9′, only on the glass pane 1, thereby establishingelectrical contact with the deactivated regions s₁, s₂ of the layer 2.These deactivated regions, insulated from the rest of the layer, willmake electrical contact with the ends of the wires 4, also allowing theupper conductive layer to be powered. In this way, the deactivatedregions of the lower electrode are exploited so that the upper electrodecan be powered via the conductive wires.

EXAMPLE 5

[0108] This is the configuration of FIG. 5, which is close to theexample 1 shown in FIG. 1, however with three differences:

[0109] In this case, the margins of the active stack are set over itsentire periphery, with four, rather than two, incision lines l₈, l₉,l₁₀, l₁₁ on each of the stack edges. An inactive region s₅ is thereforecreated, which follows the periphery of the active stack 3.

[0110] Furthermore, in this case, the margins of the lower conductivelayer 2 are not set.

[0111] However, in order to avoid short circuits, this configurationuses electrical insulation strips (of the adhesive insulating polymertype on one of its faces). These strips 12, 12′ are inserted between allthe layers and the current leads, at the two opposed edges of thesystem, so as to delimit regions identical to the regions s₆, s₇ ofExample 3. These regions in fact overlap the conductive layer 2 notcoated with layers and the conductive layer coated with the active stack3, and “cover” the entire region where the ends of the wires 4 exceedthe active stack 3.

[0112] In this way, a margin-setting operation is replaced by usingadditional insulating strips.

EXAMPLE 6

[0113] This is the configuration of FIG. 6. It comes very close toExample 1 (FIG. 1).

[0114] The only difference relates to the way in which the lowerconductive layer 2 is deactivated locally: instead of making incisionlines, the layer has been completely removed from the regionscorresponding to regions s₁ and s₂ of FIG. 1. Either it is effectivelyremoved, before depositing the active stack 3, by laser ablation orother etching techniques, or it is deposited directly with the desireddimensions on the glass pane which is already cut with a suitable mask.In both cases, this leads to a layer 2 of rectangular type surmounted bythe active system 3 and by the upper electrode, also of rectangularoutlines whose longest length is perpendicular to that of the layer 2.

EXAMPLE 7

[0115] This is the configuration of FIG. 7. It comes very close to thatof FIG. 6. It differs therefrom by the type of current lead used: inthis case, standard clips in the form of 3 mm-wide silvered copperstrips are in fact used:

[0116] strips 14 a, 14 b, 14 c to power the lower conductive layer 2,

[0117] strips 15 a, 15 b, 15 c to power the upper conductive layer viathe end of the wires 4 of the conductive network (in fact twosuperimposed clips sandwich the end of the wires 4).

[0118] These strips are electrically connected to a single socket 16. Inorder to avoid a short circuit between the strips 14 a and 15 a, forexample an electrically insulating polymer film 17 is inserted betweenthe two strips.

EXAMPLE 8

[0119] This configuration, shown in FIG. 8, comes very close to that ofFIG. 6. It differs therefrom by the type of current lead used: in thiscase, the same standard silvered copper clips as those in Example 7 areused. In this example 8, there are therefore two sockets 18, 19, each iselectrically connected to two superimposed clips 20 a, 20 b intended topower the upper conductive layer via the end of the wires 4, and to aclip 21 a, 21 b intended to power the lower conductive layer 2. Theclips are connected to the sockets by welding.

EXAMPLE 9

[0120] This configuration, shown in FIG. 9, comes very close to that ofFIG. 7. However, in the case of Example 9, only part of the carriersubstrate is covered by the lower conductive layer. This happens eitherby removing the lower conductive layer after deposition by a suitablemeans (acid attack, mechanical attack or laser ablation) or by maskingpart of the substrate before deposition of the latter. The lattertechnique is preferred in the case of large dimensions. The benefit ofthis embodiment is to produce regions which are not electricallyconductive and to be able to move the clips around the active regionwithout a risk of short circuits. By means of suitable positioning ofthe clips and the electrical insulator, the whole glazing is powered bya single electrical output, with cost saving and increased simplicity ofmounting.

EXAMPLE 10

[0121] This configuration, shown in FIG. 10, is close to that shown inFIG. 9, but the lower conductive layer is masked on three sides insteadof two. Electrical insulation is provided by setting the margins of thelower conductive layer with a laser along a line z. The advantage withrespect to FIG. 9 is that the use of a laser is simpler than handlingmasks.

EXAMPLE 11

[0122] This configuration is shown in FIG. 11. The lower conductivelayer is deposited over the entire surface of the carrier substrate. Thevarious margins are set after depositing the active layers. Moreover, aperipheral ablation is carried out over the entire periphery of theglazing in order to avoid the short circuits which could occur by meansof the edges.

EXAMPLE 12

[0123] This configuration is shown in FIG. 12. To prevent any shortcircuit at the wires, a double margin y is made in the region CC. Thefirst is made after depositing the lower conductive layer with a widthof 1 mm to 50 mm. The second, which is thinner (100 to 500 μm) is madeover the trace of the previous one, after depositing the active layers.The wires are separated from the lower conductive layer by the wholestack and there is no longer a risk of a short circuit.

[0124] In conclusion, the invention makes it possible for many variantsin the way of powering systems of the electrochromic type (or systems ofthe viologen, light valve, liquid crystal type and any similarelectrochemical system). It is possible to envision using a network ofconductive wires or of screen-printed conductive strips for the lowerelectrode, in the place of or in addition to wires used in the examplesfor the upper electrode. Various current leads can be used, includingstandard clips or flexible polymer strips provided with conductivecoatings. Current leads which are particularly discreet can also beused, such as simple conductive wires or even point-like current leads.

[0125] Depending on the type of mounting, it is possible to arrive athaving only two sockets, and even a single socket, which makes it veryeasy to power the device.

[0126] It is possible to make devices of the electrochromic glazing typewith very diverse geometries, even though the examples, for reasons ofsimplicity, describe active stacks with a rectangular surface area.

[0127] The invention lies in the fact of separating the visible electricleads to the periphery of the active layers delimiting the actual activeregion of the glazing, while avoiding short circuits between the twoelectrodes by means of various types of margin setting. It selectively“deactivates” one or other of the electrodes and/or of the active layersand/or chooses suitable relative positions and dimensions in order toachieve this.

[0128] The invention is applicable in the same way to photovoltaicdevices, and, more generally, to any electrically controllable orphotovoltaic system which comprises at least one “upper” (or “lower”)conductive electrode in the sense of the invention: indeed, it is alsowithin the scope of the invention to alter the position with respect tothe “active” layers only of the current lead or leads of only one of theelectrodes and not of the two electrodes (either by choice, or becausethe device in question contains only a single electrode of the typedescribed above, that is with one electroconductive layer).

[0129] In the case where the lower electrode and the rest of the stackof layers of the active system are incised along the same line, it maybe advantageous to provide for the incision line of the lower electrodeto be larger than the incision line for the rest of the layers, forelectrical considerations: the two incision lines are superimposed andare centered one with respect to the other, in this way, the conductiveregions of the lower electrode avoid being left bare (it is the otherlayers which “go beyond” the incisions with respect to the lowerelectrode).

1. An electrochemical device, especially an electrically controllable system with variable energy and/or optical properties or a photovoltaic device, comprising at least one substrate (1) carrying an electroactive stack of layers (3) arranged between an electrode called a “lower” electrode and an electrode called an “upper” electrode, each comprising at least one electroconductive layer (2) in electrical contact with at least one current lead, characterized in that said current leads of at least one of the electrodes, especially of the two electrodes, are arranged outside the region of the carrier substrate (1) which is covered by the electroactive stack of layers (3).
 2. The device as claimed in claim 1, characterized in that the “lower” electrode comprises an electroconductive layer (2) which covers at least one region of the carrier substrate not covered by the electroactive stack (3).
 3. The device as claimed in one of the preceding claims, characterized in that the “lower” electrode comprises an electroconductive layer (2) which covers a region Z₁ of the carrier substrate (1) completely covering the region Z₂ of the carrier substrate covered by the electroactive stack of layers 3, and of dimensions greater than the latter.
 4. The device as claimed in claim 1 or claim 2, characterized in that the “lower” electrode comprising an electroconductive layer (2) covering a region of the carrier substrate, in particular an essentially rectangular region Z₁, and in that the electroactive stack (3) also covers a region, in particular an essentially rectangular region Z₂, of the carrier substrate, these two regions partially covering each other.
 5. The device as claimed in claim 3, characterized in that the electroconductive layer (2) of the “lower” electrode covers an essentially rectangular region Z₁ of the substrate (1) which is of larger dimensions and essentially centered on the smaller rectangular region Z₂, covered by the electroactive stack (3).
 6. The device as claimed in claim 3, characterized in that the electroconductive layer (2) of the “lower” electrode covers a rectangular region Z₁ exceeding, on two of its opposed sides only, the rectangular region Z² covered by the stack (3).
 7. The device as claimed in one of the preceding claims, characterized in that the electroconductive layer (2) of the “upper” electrode covers a region Z₃ of the carrier substrate (1) which is essentially identical to that covered by the electroactive stack
 3. 8. The device as claimed in one of the preceding claims, characterized in that the electroconductive layer (2) of the “lower” electrode is deactivated over at least part of its periphery, at least in part over a region not covered by the electroactive stack (3), especially over a region overlapping a region covered by and a region not covered by the electroactive stack (3).
 9. The device as claimed in claim 7, characterized in that the electroconductive layer 2 of the “lower” electrode covers a substantially rectangular region of the carrier substrate (1) and in that it comprises two peripheral deactivated regions (s₁, s₂), along two opposed edges of said rectangular region.
 10. The device as claimed in claim 8, characterized in that the electroconductive layer (2) of the “lower” electrode comprises a deactivated region (s₅) over its entire periphery.
 11. The device as claimed in one of claims 8 to 10, characterized in that the deactivated region(s) is (are) obtained by incision of the electroconductive layer (2) along one or more lines, in particular along a line which is closed around its entire periphery (15), or along two lines (l₁, l₂) crossing the layer from one side to the other over two of its opposed edges, or along two lines (l₆, l₇) closed along two of its opposed edges.
 12. The device as claimed in one of claims 8 to 12, characterized in that the incision of the electroconductive layer (2) is carried out after depositing the electroactive stack (3) and also possibly after that of the “upper” electrode, with simultaneous incision of all the layers when the region of the electroconductive layer to be incised is covered by the electroactive stack (3).
 13. The device as claimed in one of the preceding claims, characterized in that the electroactive stack (3) is deactivated over at least part of its periphery.
 14. The device as claimed in claim 13, characterized in that the electroactive stack (3) covers a substantially rectangular region of the carrier substrate (1) and in that it comprises two peripheral regions (s₃, s₄) deactivated along two opposed edges of said rectangular region.
 15. The device as claimed in claim 13, characterized in that the electroactive stack (3) comprises a deactivated region (s₆) over its entire periphery.
 16. The device as claimed in one of claims 13 to 15, characterized in that the deactivated region or regions of the electroactive stack (3) is (are) obtained by incision of the whole stack and possibly also of the upper electrode, along two lines (l₃, l₄) crossing the stack from one side to the other on two of its opposed edges or along a line (l₈, l₉, l₁₀, l₁₁) closed around its entire periphery, preferably without simultaneously incising the underlying “lower” electrode (2).
 17. The device as claimed in one of the preceding claims, characterized in that the lower electrode (2) and the stack of electroactive layers (3) are incised at the same location over at least part of their common surface, the two incision lines being superimposed and the incision line of the lower electrode being wider than that of the stack of electroactive layers.
 18. The device as claimed in one of the preceding claims, characterized in that at least one of the two electrodes, preferably the “upper” electrode, comprises an electroconductive layer combined with a network (4) of conductive wires/conductive strips.
 19. The device as claimed in claim 18, characterized in that the conductive network (4) comprises a plurality of essentially metal wires placed on the surface of a polymer film 5, especially of the thermoplastic type.
 20. The device as claimed in claim 17 or claim 19, characterized in that the wires/strips (4) are placed essentially parallel to each other, preferably in an orientation which is essentially parallel to the length or the width of the electroconductive layer of the “upper” electrode, the ends of said wires/strips exceeding the region of the substrate covered by said electroconductive layer on two of its opposed edges, in particular by at least 0.5 mm.
 21. The device as claimed in claim 20, characterized in that the ends of the wires/strips (4) which are outside the region covered by the electroconductive layer of the “upper” electrode are in contact with the “lower” electroconductive layer (2) only in its deactivated region or regions.
 22. The device as claimed in claim 20 or claim 21, characterized in that the ends of the wires/strips (4) which are outside the region covered by the electroconductive layer of the “upper” electrode are electrically insulated from contact with the active region of the electroconductive layer (2) of the “lower” electrode, in particular by insertion of strip(s) of insulating material.
 23. The device as claimed in one of claims 18 to 22, characterized in that the ends of the wires/strips (4) associated with the electroconductive layer of the “upper” electrode are electrically connected to two current leads in the form of flexible strips (6 a, 6 b) made of an insulating polymer covered on one or their faces with a conductive coating (7, 8).
 24. The device as claimed in one of claims 18 to 22, characterized in that the ends of the wires/strips 4 associated with the electroconductive layer of the “upper” electrode are in electrical contact with two deactivated regions of the electroconductive layer (2) of the “lower” electrode and in that said deactivated regions are in electrical contact with current leads, in particular in the form of conductive “clips” (10, 10′) clipping onto the carrier substrate (1).
 25. The device as claimed in one of the preceding claims, characterized in that the conductive layer (2) of the “lower” electrode is electrically connected to current leads, especially along two of its opposed edges, in active regions which are not covered with the electroactive stack
 3. 26. The device as claimed in claim 25, characterized in that said leads are in the form of conductive “clips” (9, 9′) clipping onto the carrier substrate (1).
 27. The device as claimed in claim 23, characterized in that all the current leads of the “lower” and “upper” electrodes are brought together in the form of two substantially identical strips (6 a, 6 b), each strip consisting of a small electrically insulating polymer support approximately in the shape of an “L”, with, on one of the sides of the “L”, a conductive coating (7) on one of the faces and on the other side of the “L” a conductive coating (8) on the face opposite to the previous face.
 28. The device as claimed in claim 27, characterized in that each L-shaped current lead (6 a, 6 b) has an external socket (12) close to the junction between the two sides of said “L”.
 29. The device as claimed in claim 23, characterized in that all the current leads of the “lower” and “upper” electrodes are brought together in the form of an approximately rectangular strip, formed from a flexible support made of an electrically insulating polymer, with, on two opposed edges, a conductive coating on one face and on its two other edges a conductive coating on the face opposite to the previous face, preferably with a single external socket.
 30. The device as claimed in one of the preceding claims, characterized in that at least one of the current leads is in the form of a clip (14, 15), in particular a metal strip, or in the form of one or more conductive wires, or in the form of a point-like lead made of a conductive material.
 31. The device as claimed in one of the preceding claims, characterized in that the electroactive stack (3) covers a region of the carrier substrate which is a polygon, a rectangle, a diamond, a trapezium, a square, a circle, a half circle, an oval, or any parallelogram.
 32. The device as claimed in claims 30 and 31, characterized in that at least one of the current leads is in the form of a conductive wire or a plurality of conductive wires following all or part of the perimeter delimiting the area of the carrier substrate covered by the electroactive stack (3).
 33. The device as claimed in one of the preceding claims, characterized in that it involves an electrochromic system, in particular of the “all-solid” type, a viologen system, a liquid crystal system, a light valve system or a photovoltaic system.
 34. The device as claimed in claim 33, characterized in that it involves an “all-solid” electrochromic glazing, in particular of laminated structure.
 35. The device as claimed in claim 34, characterized in that the electrochromic glazing comprises at least one bulk tinted glass pane and/or at least one curved glass pane.
 36. The device as claimed in one of claims 33 to 35, characterized in that it also comprises at least one of the following coatings: infrared reflecting coating, hydrophilic coating, hydrophobic coating, photocatalytic coating with antifouling properties, antireflective coating, electromagnetic shielding coating.
 37. The device as claimed in one of claims 33 to 36, characterized in that the carrier substrate (1) is rigid, semirigid or flexible. 